Tool



Aug- 27, l946- H. .1. ENGBRECHT .2,406,326

AI'ooL I Filed Jan. 19, '1944 IN V EN TOR.

Patented Aug. 27, 1946 TOOL Herman J. Engbrecht, North Hollywood, Calif., as-

signor to Bendix Aviation Corporation, North Hollywood, Calif., a corporation of California Application January 19, 1944, Serial No. 518,839

Claims.

This invention relates to tools for accurately cutting or finishing surfaces in valves and the like and is particularly usefu1 for reaming a surface in concentric relation with another surface or surfaces.

An object of the invention is to facilitate the rapid and accurate cutting of a surface in concentric relation to another surface.

l A more specic object is to provide a tool for cutting seats in valve bodies and the like which tool positively aligns the seat in true concentric relation with the passage or passages leading to the seat.

' Other more specic objects and features of the invention will appear from the detailed description to follow.

It is common in the construction of hydraulic valves to employ two aligned bores of different diameter with a conical valve seat in the end of the smaller bore where it merges into the larger bore. Heretofore, it has been the practice to ream the conical seat and/or the smaller bore with a reaming tool admitted through the larger bore. However, the prior methods did not provide any positive means for aligning the tool with the larger bore, the skill of the workman being relied upon to so support the reaming too1 that the Vresultant reamed surface would be reasonably accurately aligned with the larger bore. These previous methods have been unsatisfactory, not only because they required a considerable amount of skill on the part of the workman, but were slow, and, where accurate work was demanded, there were considerable numbers of rejections even with eflicient workmen.

In accordance with the present invention, I eliminate the need of specially skilled workmen for performing this operation by providing a seatreaming tool which has a guide structure expandable to wedge in the larger bore so that there is no possibility of the reaming too1 being misaligned, even by unskilled workmen. I further provide for the rapid assembly of the reaming tool in the valve to be reamed, by utilizing the usual threads on the valve body for expanding the guide in the larger bore.

A full understanding of the invention may be had from the following detailed description'with reference to the drawing, in which:

Fig. l is a view part in side elevation and part in section of a tool in accordance withthe invention for reaming a conical seat in a valve body, the tool being adapted for a valve body with external screw threads. y

Fig. '2,is a view part in side elevation and part in section of a tool in accordance with the invention for reaming a straight bore in a valve vbody having internal screw threads.

Fig. 3 is an end view of a collet employed in the tool, andl f body Ill.

Fig. 4 is a side view, part in elevation and part in longitudinal section of the collet.

Referring rlrst to Fig. 1, there is shown, in broken lines, a valve body III having a small bore II merging into a larger bore I2, which extends to the outer end of a tubular body portion I3, which is externally threaded as indicated at I4. As these bodies are received for finishing, the small bore II is approximately aligned with the bore I2, which in turn is at least approximately aligned with the external threads I4. To finish the body, the smallbore II must have a conical seat cut therein at its outer end, which conical seat should be in alignment with both the axis of the large bore and the axis of the threads I4, if the bore and the threads are in perfect axial alignment. If the bore and threads are not in perfect alignment with each other, the axis of the seat should be midway between the axes of the bore and the threads respectively. Furthermore, if the small bore II was not originally in accurate alignment with the large bore I2, and

external thread I E, it must be reamed to place it in alignment.

In the particular valve body IIJ shown in the` drawing, the left end portion of the large bore I2 is of slightly smaller diameter than the remainder, but this is of no particular moment insofar as the present invention is concerned.

l A too1 in accordance with the present invention for cutting a conical seat in the right end of bore II is shown in full lines in Fig. 1. It comprises a hollow body member I5 internally threaded at one end with threads I6 that are dimensioned to rather loosely engage the threads I4 on the valve Adjustably fitted in a smooth bore in the outer end of member I 5 is a sleeve I'I, the left end of which is chamfered or beveled to form a conical surface tting against the beveled interior end of an expansible collet I8, which is adapted to be expanded against the large bore I2 of the valve body Ill. To this end, there is accurately fitted within the sleeve I'I a tubular guide I 9, which extends through the expansible collet I8 and is enlarged at its left end to t loosely within the reduced end portion of the large bore I2. At the point of enlargement, the guide I9 is smoothly tapered to provide a, flared or conical `seat 20, which cooperates with the seat 2 I on the sleeve I'I to expand the collet I8 when the tool is set. A

, The guide I!! rotatably supports the stem 22 of a conical reamer 23 which is rotated to ream the conical seat at the right end of the small bore II. A handle 40 may be provided onthe outer end of the stem 22 to facilitate its actuation manually, although it is to be understood that, if desired, the stem 22 can be gripped by the chuck of a drill or the like for its actuation. In order to prevent injury to the conical 'seat cut by the 3 reamer as a result of accidental impact of the reamer against the seat while the reamer is not being turned; it is desirable to .providea helical;y spring 24 which.iscompressed between a stopli. secured to the stem 22 and the inner end of a counter bore 2% in the right endfof the guide ISLJ. l

This spring 2d retracts the reamer head 23 away from the seat as soon as the is released.

The device is actuated as followszv; irstg. thee" I'I is properly positioned..longitudinally" sleeve actuating handle 49 `VVcal reamer'23 of Fig. 1.

` distance. to form acounter bore that is in perfect within the tool body I5 and locked into. position.

by tightening set screws 2l in the body I5." Then cause the seat will vary in width at different circumferential points. conical'seat has been formed, asgdescribed with reference toFig. 1, inspection of the seat shows that the small bore is out of alignment Ywith the large bore, correction is made by applying the .tool as previously described, but with a straight reamer 35 of suitable size substituted for the coni- The cylindrical reamer isthen: advancedrinto the bore IIa for a short alignment with the conical seat and with the large b'ore.

the tool is attached to the valve body I by enten` ing the inner end of the guide IS into the large bore I 2 and screwing. the tool body I5 on tothe external threads I4` of the valve body-I0. 'This rst moves the entire tool to the leftv until ythe left end 280i the guide I9 `rests against the shouli der. at they left end, of the large bore lzgwhich stops further movement to the left of the guide. I 9.

Thereafter, as Vthe tool'body IS-is given itsiinal turns, the sleeve Il is `moved to the left relative tothe guide. I9, causing the. conical surfacesZI and 20, on the sleeve Il and the guide I9 respec; tively, to expand the collet I'tightly againstthe., large bore I2. .As clearly shown in.Figs.I3 and..4,` the colletIB hasfour slits Sil-.extending from the.,

right end approximately three quarters v.of the way to the left end,. andfour slits .3l extending from. the left endapproximatelythree quartersof .the 1 wayto theright end, the slits .3| being circumfery entially positioned midway between adjacent .slits 30. The colletis therefore free. toexpand, .in rev sponse to the wedging action'applied thereto by'. the conical surfacesZII and 2 i, until its outer surface is expanded. tightly against the., bore'. I2,..v which occurs when thetool body I5 has been. fully` tightened.

As hasbeen previously mentioned, thethreads I6 inthe tool body I5 .are cut to t loosely on the threads I 4 of the .valve body, so that, if the threads: I4.are not Aexactlycoaxial'withy the large bore -.I2,.

the toolbody I5 can cock .slightly with respect to.threads.-II,.i'lo` permit the guide I9 to. assume av position .in which its axisis intermediatethe. axis of the bore. I2 andthe threads Iirespectively.

After the toolhasbeen positioned as described', the conical seat is reamed at the right end of the small, bore AII by pressing the handleo to the left. and rotatingit.

The stop 25,. collar for the compression of the` spring 24also functions as a stop to limit the depthof out made by the conical reaxner 23. Thus, the stop.25 may .besecured to the stem 22 of the reamer by an Allenset screw 32, and by loosening .this screw, the stop 25 vcan be so positioned cnthe stem.22

aste contact the outer end 33 of the guide I9` when the reamer has lcut to the desired depth.

Referring noW toFig. 2, there is shown a tool substantially identical with thatdescribed with reference to. Figs. 1, 3 Vand 4 except. that thebo'dy.`

I5 is provided with external threads 34 to it -in.

'ternal threads 35. in another branch of the valvei body I0, and a straight reamer 35 is substituted. for the conical reamer 23 ofFig. l. It may be assumed that in Fig. 2 aconical seat 31 has'already been reamed at the lower end of the passage IIa by employing in the tool of Fig. 2 a conical-reamer similar 4to reamer .23. lof Fig. l, and that tit has been discovered, after the formation ofthe seat' 31,1 that the bore. I Ia is out of alignment ywith the bore `I2a. Such misalignment can beV readily de-` tectedafter. the conical seaizh'asbeenV cut, be-

in, addition to .functioningas a:

Although for the purposes of explaining the invention a specific embodiment thereof has been described indetail withv reference to the drawing, it is to be understoodthat the invention isnot.

limitedto exact structuresv described but. only-to.

the extent .setforthinthe appended claims. I claim: Y l. A tool fcrmachininga body having a-.cylindrical bore and screw threads inv at leastapproximately concentric relation'tov saidbore, to .produce in said. body a surface yoirevolution in ,approximate axialalignment with said bore', said toolv comprising: Va'nollow guidedimensioned to enter said. bore; a rotatable.v tool accurately guided .by said guide for rotary and longitudinal movement coaxial with said. guide; andmeans for positively positioning said guide withinsaid bore, compris.- ing an expansible annular member surrounding` said guide and an annular wedgemember aligned with and relatively axially moveable with respectto said guide, at leastfone of said.. members .having. a conical surface .cooperativewith the other member to expand said expansible annular member against said. borein responseto relative axial movement cf-.said-members towardeach other,

and means vfor eiecting. said relative. axial move-y ment including. means forlimiting axial. move.- ment of said expansiblemember into said bore,- and nut means adaptedfto engage thethreadsof said body, for moving said wedge member-'againstl said expansible member.

` 2. A tool asdescribedin claim 1 forreamingY a Ybody havingexternal threads surrounding saidv bore, in which said nut .means comprises a. skirt adaptedv to .telescope over the threaded portion of said .body member Yand havinginternal threads to engage therewith. n .f SpA-tool as. described in claim 1 for reaminga body in which the.. outer end .portion of said large bore. is internally threaded, in. which said nut meanscomprises an annularv member dimensioned tov enter saidlarge bore and externally threaded` to engage with .said .threads in .the body.

. 4. .A -tool as described in claim 1 in which said expansible annulanmemberhas .two expansible annular, bore-contacting faces at-opposite ends thereof, and.. cooperating. faces on oneend of` said annular member and said guide, and-.cooperating faces on the `other end of saidv annular. member and. said wedge member, whereby both'ends of said annularmember are. expanded against ,saidv Therefore, if, after the.

tightening ,said 

